MONDAY, March 24, 2014 (HealthDay News) -- Where you're treated for ovarian or other gynecologic cancers makes a difference. Women with these conditions live more than a year longer on average if they're treated at hospitals that deal with a large number of these cancers, according to a new study.

Researchers looked at data from more than 860,000 patients with ovarian, cervical, uterine, vaginal or vulvar cancer who were treated at nearly 1,700 centers across the United States.

Median survival was about 10 years and three months for patients treated at the highest-volume hospitals (nearly 300 gynecologic cancer patients a year) and a little more than nine years for those treated at the lowest-volume hospitals (fewer than 20 gynecologic cancer patients a year), a difference of more than a year.

The survival gap was even larger among women with cancers that are rare or require complex management. Median survival time was more than four years for ovarian cancer patients treated at high-volume hospitals and about two and a half years for patients at low-volume hospitals.

Vaginal cancer patients treated at high-volume hospitals had a median survival of six years compared to a little more than three years for those treated at low-volume hospitals, according to the study, which was scheduled for presentation Monday at a Society of Gynecologic Oncology meeting in Tampa, Fla.

There are a number of possible reasons patients treated at high-volume hospitals live longer, said study lead author Dr. Jeff Lin, a physician in the division of gynecologic oncology at the Magee-Womens Hospital at the University of Pittsburgh Medical Center.

Those reasons include better coordination of care, greater access to clinical trials that provide the latest treatments, and a better chance of being treated by gynecologic oncologists, who specialize in these types of cancers.

The researchers also found that the number of patients treated at high-volume centers increased from less than 200 per year in 1998 to nearly 300 per year in 2011.

But they also found that elderly patients and those with more advanced disease were less likely to be treated at high-volume hospitals. For example, a 75-year-old patient was 20 percent less likely to be treated at a high-volume hospital than a woman of 50.

Data and conclusions presented at meetings typically are considered preliminary until published in a peer-reviewed medical journal.